I stumbled across this great article on MossAndStoneGardens.Com today.
First, do you know your Acrocarp from your Pleurocarp? Yeah, me either.
Also you should prepare the surface where you'll want the moss to grow, remembering "that moss will follow the small undulations that are normally not noticeable until a smooth carpet of green is hugging the ground."
Also moss grows wicked slowly, so get ready for a whole lot of nothing for a bit as it takes hold.
Read the full article here: How to Grow Moss.
It has tips on when and how to water moss, how to collect moss, and even a bunch of humorous images of a moss faery dude on a moss lawn. Now that's what I call mossome.